STUDIES ON THE APPLICABILITY OF BIOMARKERS IN ESTIMATING THE SYSTEMICBIOAVAILABILITY OF POLYNUCLEAR AROMATIC-HYDROCARBONS FROM MANUFACTURED-GAS PLANT TAR-CONTAMINATED SOILS

The systemic bioavailability of polynuclear aromatic hydrocarbons (PAH ) from ingested soils containing manufactured gas plant (MGP) tar was evaluated in mice. Soil and organic extract of each soil were incorpor ated into a diet and fed to mice for two weeks. l-Hydroxypyrene levels in urine and chemical:DNA adduct levels in lungs were used as biomark ers of PAH systemic bioavailability. Estimates of PAH relative bioavai lability were determined by comparing the bioavailability observed bet ween each soil and corresponding organic extract. In all but one case, bioavailability estimates based on l-hydroxypyrene levels in urine in dicate that the presence of MGP tar on soil results in a considerable decrease in PAH systemic bioavailability (9-75%). Similarly, PAH bioav ailability estimates based on chemical:DNA adduct formation ranged fro m nondetectable to 76%. These results clearly indicate that the bioava ilability of PAH is less than 100% when soil contaminated with MGP tar is ingested by mice. In addition, the experimental methods employed i n this study appear suitable for evaluating the effects of soil on the gastrointestinal absorption and systemic bioavailability of PAH from soil containing complex organic mixtures.